Preparation and characterization of chitosan-poly(acrylic acid) polymer magnetic microspheres

A modified method to prepare chitosan-poly(acrylic acid)(CS-PAA) polymer magnetic microspheres was reported in this paper. First, via self-assembly of positively charged CS and negatively charged Fe₃O₄ nanoparticles, magnetic CS cores with a large amount of Fe₃O₄ nanoparticles were successfully prepared. Subsequently, the AA monomers were polymerized on the magetic CS cores based on the reaction system of water-soluble polymer-monomer pairs. These polymer magnetic microspheres had a high Fe₃O₄ loading content, and showed unique pH-dependent behaviors on the size and zeta potential. From the magnetometer measurements data, the CS-PAA polymer magnetic microspheres also had superparamagnetic property as well as fast magnetic response. A continuous release of the entrapped ammonium glycyrrhizinate in such polymer magnetic microspheres occurred, which confirmed the potential applications of these microspheres for the targeted delivery of drugs.     

3D gel printing of magnetic hydrogel scaffolds assisted by in-situ gelation in a water level-controlled crosslinker bath

Polyvinylalcohol/chitosan (PVA/CS) is an excellent dual-network hydrogel material, but some significant challenges remain in fabricating composites with specific structures. In this study, 3D gel printing (3DGP) combined with a water-level controlled crosslinker bath was proposed for the rapid in-situ prototyping of PVA/CS/Fe₃O₄ magnetic hydrogel scaffolds. Specifically, the PVA/CS/Fe₃O₄ hydrogels were extruded into the crosslinker water to achieve rapid in-situ gelation, improving the printability of hydrogel scaffolds. The effect of the PVA/CS ratio on the rheological and mechanical properties of dual-network magnetic hydrogels was evaluated. The printing parameters were systematically optimized to facilitate the coordination between the crosslinking water bath and printer. The different crosslinking water baths were investigated to improve the printability of PVA/CS/Fe₃O₄ hydrogels. The results showed that the printability of the sodium hydroxide (NaOH) crosslinker was significantly better than that of sodium tripolyphosphate (TPP). The magnetic hydrogels (PVA: CS= 1: 1) crosslinked by NaOH had better compressive strength, swelling rate, and saturation magnetization of 1.17 MPa, 92.43%, and 22.19 emu/g, respectively. The MC3T3-E1 cell culture results showed that the PVA/CS/Fe₃O₄ scaffolds promoted cell adhesion and proliferation, and the scaffolds crosslinked by NaOH had superior cytocompatibility. 3DGP combined with a water-level controlled crosslinker bath offers a promising approach to preparing magnetic hydrogel materials.     

The synthesis and characterization of monodispersed chitosan-coated Fe3O4 nanoparticles via a facile one-step solvothermal process for adsorption of bovine serum albumin

Preparation of magnetic nanoparticles coated with chitosan (CS-coated Fe₃O₄ NPs) in one step by the solvothermal method in the presence of different amounts of added chitosan is reported here. The magnetic property of the obtained magnetic composite nanoparticles was confirmed by X-ray diffraction (XRD) and magnetic measurements (VSM). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) allowed the identification of spherical nanoparticles with about 150 nm in average diameter. Characterization of the products by Fourier transform infrared spectroscopy (FTIR) demonstrated that CS-coated Fe₃O₄ NPs were obtained. Chitosan content in the obtained nanocomposites was estimated by thermogravimetric analysis (TGA). The adsorption properties of the CS-coated Fe₃O₄ NPs for bovine serum albumin (BSA) were investigated under different concentrations of BSA. Compared with naked Fe₃O₄ nanoparticles, the CS-coated Fe₃O₄ NPs showed a higher BSA adsorption capacity (96.5 mg/g) and a fast adsorption rate (45 min) in aqueous solutions. This work demonstrates that the prepared magnetic nanoparticles have promising applications in enzyme and protein immobilization.     

Chitosan- and dehydroascorbic acid-coated Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> nanoparticles: preparation,characterization and their potential as draw solute in forward osmosis process

Forward osmosis (FO) is a natural osmosis process that has attracted a significant attention due to its many advantages. However, the development of FO process depends on the development of proper draw solutions. In this work, chitosan (CS)-coated Fe₃O₄ nanoparticles and dehydroascorbic acid (DHAA)-coated Fe₃O₄ nanoparticles were successfully synthesized by co-precipitation method and their performance as draw solutes was investigated for application in FO systems. CS and DHAA could improve the surface hydrophilicity of the Fe₃O₄ nanoparticles. The synthesized nanoparticles were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometry (VSM) which the results presented a small size, crystalline morphology and high magnetization value for their structure as well as a good dispersion in water. Cellulose triacetate/cellulose acetate (CTA/CA)-based membranes were also prepared by immersion precipitation and used as FO membranes. The synthesized FO membranes were characterized by FESEM. The performance evaluation of synthesized nanoparticles revealed that the water flux of Fe₃O₄ nanoparticles capped with DHAA was higher than that of the chitosan-coated Fe₃O₄ nanoparticles. At the end of the process, the Fe₃O₄ nanoparticles were easily separated from the diluted draw solution by applying the magnetic field.     

Preparation and sedimentation behavior of conductive polymeric nanoparticles

A facile route to prepare Fe₃O₄/polypyrrole (PPY) core-shell magnetic nanoparticles was developed. Fe₃O₄ nanoparticles were first prepared by a chemical co-precipitation method, and then Fe₃O₄/PPY coreshell magnetic composite nanoparticles were prepared by in-situ polymerization of pyrrole in the presence of Fe₃O₄ nanoparticles. The obtained nanoparticles were characterized by scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and laser particle size analyzer. The images indicate that the size of Fe₃O₄ particles is about 10 nanometers, and the particles are completely covered by PPY. The Fe₃O₄/PPY core-shell magnetic composite nanoparticles are about 100 nanometers and there are several Fe₃O₄ particles in one composite nanoparticle. The yield of the composite nanoparticles was about 50%. The sedimentation behavior of Fe₃O₄/PPY core-shell magnetic nanoparticles in electrolyte and soluble polymer solutions was characterized. The experimental results indicate that the sedimentation of particles can be controlled by adjusting electrolyte concentration, solvable polymers and by applying a foreign field. This result is useful in preparing gradient materials and improving the stability of suspensions.     

In-situ grown Ag on magnetic halloysite nanotubes in scaffolds: Antibacterial,biocompatibility and mechanical properties

A novel design of antibacterial and magnetic halloysite nanotubes loaded with Ag and Fe₃O₄ was reported. In detail, magnetic nanoparticles (Fe₃O₄) were immobilized on the surface of halloysite nanotubes (HNTs) via electrostatic adsorption (termed as HNTs/Fe₃O₄). The magnetic HNTs/Fe₃O₄ was then modified by polydopamine to in-situ grow Ag nanoparticles by a redox reaction, forming a composite nanostructure of HNTs/Fe₃O₄@Ag. The HNTs/Fe₃O₄@Ag was incorporated into poly-l-lactic acid (PLLA) scaffold fabricated via selective laser sintering, with the intent to endow the scaffold with robust antibacterial function and favorable cell activity. The results showed that the released Ag⁺ from the scaffold significantly against E. coli activity, with bacterial inhibition rate above 99%. Moreover, ion release behavior showed a scaffold enable to sustain release Ag⁺ over 28 days. Furthermore, Fe₃O₄ nanoparticles constructed magnetic microenvironment greatly enhanced cell activity and promoted cell proliferation. In addition, tensile strength of the scaffold increased by 52.9% compared with PLLA scaffold. These positive results suggested that the HNTs/Fe₃O₄@Ag nanostructure possessed potential in facilitating bone repair.     

Influence of magnetic casting on the permeability and anti-fouling properties of a novel iron oxide/alumina/polysulfone mixed matrix membrane

Novel mixed matrix membranes (MMMs) were fabricated using Fe₃O₄, and Al₂O₃ nanoparticles (NPs) were added to the polysulfone (PSf) and N-methylpyrrolidone (NMP) solution. The nanocomposite membranes were fabricated using the NIPS (non-solvent induced phase separation) method. In order to create preferential permeation pathways for water across the MMMs, membrane formation is accomplished with an external magnetic field. Using magnetic casting cause the targeted placement of NPs in the best location and orientation. The performance of the prepared membranes was examined in terms of pure water flux and fouling parameters. Magnetic casting considerably increased pure water flux and decreased the total resistance of the optimum mixed matrix membrane, which contains 0.2% wt. of Fe₃O₄ NPs to 1175 L/m²h and 13.4 * 10¹¹ (m⁻¹), respectively. This is explained by the ordering of magnetic nanoparticles on the membrane sub-layer cast under the magnetic field of 500 mT, which changed the sub-layer structure. Less rough membrane surface of the mixed matrix membranes offered preferable anti-fouling properties against fouling by BSA proteins. The characterization of fabricated membranes was carried out using field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), energy dispersive X-ray (EDX), and water contact angle measurement methods.     

Adsorption of reactive yellow 145 onto chitosan coated magnetite nanoparticles

Removal of dyes from the industrial discharge water is an important issue for safety of the environment. In this study, magnetic (magnetite, Fe₃O₄) nanoparticles were coated with chitosan (CS) and the efficiency of these chitosan coated magnetic nanoparticles (Fe₃O₄‐CS) for the adsorption of a reactive textile dye (Reactive Yellow 145, RY145) was examined first time in literature. TEM, XRD, and EPR results revealed that the thickness of the coat was about 2–5 nm, no phase change in the spinel structure of magnetic particles existed after coating, and particles had paramagnetic property, respectively. Adsorption of RY145 on Fe₃O₄‐CS nanoparticles occurs according to Langmuir model in the temperature range 25°C–45°C with a maximum adsorption capacity of 47.62 mg g^?1 at 25°C, in aqueous media. Thermodynamic parameters demonstrated that the adsorption process was endothermic and spontaneous, and the maximum desorption of the dye was 80% over a single adsorption/desorption cycle. In this study, the high efficiency of the CS coated magnetic nanoparticles in the adsorption and removal of reactive dyes from water was shown on model RY145. This type of nanoparticles can be good candidates in industrial applications for the decolorization of waste waters. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Layer-by-Layer Engineered Superparamagnetic Polyelectrolyte Hybrid Hollow Microspheres With High Magnetic Content as Drug Delivery System

Polyelectrolyte hybrid hollow microspheres with sandwich structure of about 450 nm have been accomplished by layer-by-layer self-assembling of two modified ferroferric oxide nanoparticles, lysine modified ferroferric oxide nanoparticles (Fe₃O₄-LYs) and citrate modified ferroferric oxide nanoparticles (Fe₃O₄-CA), as the main assembling materials via electrostatic interaction for the first time. They are superparamagnetic with saturation magnetization of 45.69 emu/g, revealing their high magnetic content of 70%. As drug delivery system, they also exhibited pH-stimuli responsive controlled release of an anticancer drug doxorubicin, following the Fickian diffusion model. Their unique structure and high magnetic content make them good candidate for targeted delivery.     

Synthesis and properties of magnetic sensitive shape memory Fe3O4/poly(ε‐caprolactone)‐polyurethane nanocomposites

Fe₃O₄/poly (ε‐caprolactone)‐polyurethane (PCLU) shape memory nanocomposites were prepared by an in situ polymerization method. The thermal properties, magnetic properties, and shape memory properties of the nanocomposites were investigated systematically. The results showed that the Fe₃O₄ nanoparticles were homogeneously dispersed in the PCLU matrix, which ensured good shape memory properties of nanocomposites in both hot water and an alternating magnetic field (f = 45 kHz, H = 29.7 kA m^?1/36.7 kA m^?1). The nanocomposites started to recover near 40°C, which is slightly higher than body temperature. Thus, they would not change their deformed shape during the implanting process into the human body. Considering potential clinical applications, 45°C was chosen as shape recovery temperature which is slightly higher than 37°C, and the nanocomposites had high shape recovery rate at this temperature. With increasing content of Fe₃O₄ nanoparticles, the shape memory properties of the nanocomposites in an alternating magnetic field increased and the best recovery rate reached 97%, which proves that this kind of nanocomposites might be used as potential magnetic sensitive shape memory materials for biomedical applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013     

Preparation and evaluation of chitosan/β‐cyclodextrin magnetic nanoparticles as a photodegradable and hydrophobic drug delivery carrier

In this study, novel tumor targeting nanocarriers comprised of chitosan (CS)/β‐cyclodextrin (β‐CD) magnetic nanoparticles were prepared to improve the photodegradable stability and bioavailability of hydrophobic drug. Resveratrol (Res) with photodegradable and hydrophobic properties was selected as a model drug. The photodegradation rate of Res in Fe₃O₄ nanoparticles solution was 7.8 times lower than that in the ethanol solution_. In addition, the value of the saturation magnetization of CS/β‐CD nanoparticles was found to be 19.56 emu/g with characteristic of superparamagnetism. Approximately 90% Res was entrapped into the CS/β‐CD magnetic nanoparticles with the size distribution ranging from 200 to 359 nm, and the nanoparticles were spherical in shape with high zeta potentials. Furthermore, the formation of CS/β‐CD nanoparticles showed a sustained release in vitro. These results indicated that the obtained CS/β‐CD magnetic nanoparticles were a promising magnetic targeting carrier for photodegradable and hydrophobic drugs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45076.     

A sonochemical method for synthesis of Fe3O4 nanoparticles and thermal stable PVA-based magnetic nanocomposite

Fe₃O₄ nanoparticles were synthesized via a simple surfactant-free sonochemical reaction. Room temperature synthesis without using inert atmosphere is the novelty of this work. The effect of different parameters on the morphology of the products was investigated. The magnetic properties of the samples were also investigated using an alternating gradient force magnetometer. Fe₃O₄ nanoparticles exhibit a ferromagnetic behavior with a saturation magnetization of 66 emu/g and a coercivity of 39 Oe at room temperature. For preparation magnetic nanocomposite, Fe₃O₄ nanoparticles were added to the polyvinyl alcohol (PVA). Nanoparticles can enhance the thermal stability and flame retardant property of the PVA matrix.     

Enhanced dielectric,ferroelectric and magnetic properties of Ba4Sm2Fe2Nb8O30 RT multiferroics prepared by microwave sintering

High density Ba₄Sm₂Fe₂Nb₈O₃₀ (BSFN) multiferroics ceramics with tetragonal tungsten bronze structure had been prepared by microwave sintering (MS) for 30min and conventional sintering (CS) methods for 4 h at 1275 °C. Single tungsten bronze phase and equiaxial grains are obtained for the MS BSFN ceramics, while a small amount secondary phase of SmNbO₄ is observed in the CS BSFN ceramics with columnar grains. Compared to Ba₄Sm₂Fe₂Nb₈O₃₀ ceramics prepared by CS method, enhanced dielectric, ferroelectric and magnetic properties are achieved for the MS BSFN ceramics. The values of electric polarization Pr and coercive electric field Ec are 2.11 μC/cm² and 7.14 kV/cm for the MS BSFN ceramics, respectively. Meantime, the magnetic polarization Mr of 0.410emu/g and coercive magnetic field Hc of 2930Oe are also obtained for the MS BSFN ceramics. Based on the density, crystal structure, point defect and grain, the reasons of enhanced dielectric, ferroelectric and magnetic properties are discussed for the MS BSFN ceramics It is indicated that Ba₄Sm₂Fe₂Nb₈O₃₀ is an intrinsic room temperature multiferroic materials.     

Elastic geopolymer based on nanotechnology: Synthesis,characterization, properties,and applications

Geopolymers are an economical, durable and environmentally friendly building material that achieves ultimate strength superior to concrete within hours and can withstand extreme high temperatures without degradation, but they lack elasticity and have poor flexural strength. To tackle these challenges, this paper presents a novel nanotechnological and affordable method to produce an elastic geopolymer that can be used as a construction material. Specifically, we report a simple and straightforward strategy that combines electrospinning and the sol-gel process to construct geopolymer nanofibers with superelasticity, extreme durability, and fire resistance. In order to improve the safety level of building construction sites that experience extreme conditions, such as freeze-thaw deterioration, the geopolymer nanofibers can be further functionalized by incorporating various functional components. In this study, Fe₃O₄ nanoparticles (NPs) adsorbed by an electric double layer structure were dispersed in a geopolymer sol (SAPOs). Elastic geopolymer nanofibers embedded with Fe₃O₄ nanoparticles were then prepared (Fe₃O₄/SAPOs) by an electrospinning method. Nanofibers constructed by such a compound method could have superparamagnetic behaviors and stable chemical properties. When Fe₃O₄/SAPOs are exposed to an alternating magnetic field, eddy currents are generated that cause the geopolymer nanofibers to heat up. This self-heating behavior is a powerful feature that enhances the freeze-thaw resistance of building materials at high altitudes. The nanotechnological route of this study could provide novel insights into the development of advanced construction materials.     

Enhanced Heat Transfer Properties of Magnetite Nanofluids due to Neel and Brownian Relaxation Mechanisms

Fe₃O₄ nanoparticles were prepared through solvo-thermal method for further heat transfer applications. TEM, XRD, TGA, and VSM were applied to characterize the obtained nanoparticles. XRD pattern confirmed that nanoparticles were composed of 6-nm crystallites; however, TEM images showed the formation of ca. 75-nm highly dispersed magnetite clusters, made up of about 6-nm nanoparticles. Since, VSM analysis confirmed the superparamagnetic characteristics of Fe₃O₄ nanoclusters, heat transfer properties of the resulting nanofluids were studied to investigate the influence of the magnetic field on the behavior of the magnetite-based nanofluids. The findings indicated that the convective heat transfer coefficient increased up to 48% and 15%, respectively, for nanofluids containing 0.005 wt% magnetite particles dispersed in water and EG, when the frequency of the alternating magnetic field was changed from 50 Hz to 1 MHz. According to the results, compared to the water-based nanofluids, at higher field amplitudes, the h enhancements of EG-based ones were more pronounced, for instance, at H₀ = 36,000 A/m, the h measurements are augmented by about 74% and 109%, respectively, compared to the water and EG as the base fluids. These findings could be explained by the use of specific lost powers of the nanofluids in the exposure of an external alternating magnetic field.     

Preparation and characterization of magnetic poly(styrene–glycidyl methacrylate) microspheres for highly efficient protein adsorption by two‐stage dispersion polymerization

Micrometer‐sized superparamagnetic poly(styrene–glycidyl methacrylate)/Fe₃O₄ spheres were synthesized by two‐stage dispersion polymerization with modified hydrophobic Fe₃O₄ nanoparticles, styrene (St), and glycidyl methacrylate (GMA). The morphology and properties of the magnetic Fe₃O₄–P (St‐GMA) microspheres were examined by scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, thermogravimetric analysis, and attenuated total reflectance. The average size of the obtained magnetic microspheres was 1.50 μm in diameter with a narrow size distribution, and the saturation magnetization of the magnetic microspheres was 8.23 emu/g. The magnetic Fe₃O₄–P (St‐GMA) microspheres with immobilized iminodiacetic acid–Cu²⁺ groups were used to investigate the adsorption capacity and selectivity of the model proteins, bovine hemoglobin (BHb) and bovine serum albumin (BSA). We found that the adsorption capacity of BHb was as high as 190.66 mg/g of microspheres, which was 3.20 times greater than that of BSA, which was only 59.64 mg/g of microspheres as determined by high‐performance liquid chromatography. With a rather low nonspecific adsorption, these microspheres have great potential for protein separation and purification applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43005.     

Transmittance Measurements in Non-alternating Magnetic Field as Reliable Method for Determining of Heating Properties of Phosphate and Phosphonate Coated Fe3O4 Magnetic Nanoparticles

Different phosphates and phosphonates have shown excellent coating ability toward magnetic nanoparticles, improving their stability and biocompatibility which enables their biomedical application. The magnetic hyperthermia efficiency of phosphates (IDP and IHP) and phosphonates (MDP and HEDP) coated Fe₃O₄ magnetic nanoparticles (MNPs) were evaluated in an alternating magnetic field. For a deeper understanding of hyperthermia, the behavior of investigated MNPs in the non-alternating magnetic field was monitored by measuring the transparency of the sample. To investigate their theranostic potential coated Fe₃O₄-MNPs were radiolabeled with radionuclide ¹⁷⁷Lu. Phosphate coated MNPs were radiolabeled in high radiolabeling yield (>?99%) while phosphonate coated MNPs reached maximum radiolabeling yield of 78%. Regardless lower radiolabeling yield both radiolabeled phosphonate MNPs may be further purified reaching radiochemical purity of more than 95%. In vitro stabile radiolabeled nanoparticles in saline and HSA were obtained. The high heating ability of phosphates and phosphonates coated MNPs as sine qua non for efficient in vivo hyperthermia treatment and satisfactory radiolabeling yield justifies their further research in order to develop new theranostic agents.

     

磁性Fe3O4纳米粒子用作靶向药物载体的制备及分析

Fe3O4 magnetic nanoparticles were prepared by the aqueous co-precipitation of FeCl3-6H2O and FeCl2-4H2O with addition of ammonium hydroxide. The conditions for the preparation of Fe3O4 magnetic nanoparticles were optimized, and Fe3O4 magnetic nanoparticles obtained were characterized systematically by means of transmission electron microscope （TEM）, dynamic laser scattering analyzer （DLS） and X-ray diffraction （XRD）. The results revealed that the magnetic nanoparticles were cubic shaped and dispersive, with narrow size distribution and average diameter of 11.4 nm. It was found that the homogeneous variation of pH value in the solution via the control on the dropping rate of aqueous ammonia played a critical role in size distribution. The magnetic response of the product in the magnetic field was also analyzed and evaluated carefully. A 32.6 mT magnetic field which is produced by four ferromagnets was found to be sufficient to excite the dipole moments of 0.05 g Fe3O4 powder 2 cm far away from the ferromagnets. In conclusion, the Fe3O4 magnetic nanoparticles with excellent properties were competent for the magnetic carders of targeted-drug in future application.     

Preparation of chitosan‐coated magnetite nanoparticles and application for immobilization of laccase

In this study, immobilization of laccase (L) enzyme on magnetite (Fe₃O₄) nanoparticles was achieved, so that the immobilized enzyme could be used repeatedly. For this purpose, Fe₃O₄ nanoparticles were coated and functionalized with chitosan (CS) and laccase from Trametes versicolor was immobilized onto chitosan‐coated magnetic nanoparticles (Fe₃O₄‐CS) by adsorption or covalent binding after activating the hydroxyl groups of chitosan with carbodiimide (EDAC) or cyanuric chloride (CC). For chitosan‐coated magnetic nanoparticles, the thickness of CS layer was estimated as 1.0–4.8 nm by TEM, isoelectric point was detected as 6.86 by zeta (ζ)‐potential measurements, and the saturation magnetization was determined as 25.2 emu g^?1 by VSM, indicating that these nanoparticles were almost superparamagnetic. For free laccase and immobilized laccase systems, the optimum pH, temperature, and kinetic parameters were investigated; and the change of the activity against repeated use of the immobilized systems were examined. The results indicated that all immobilized systems retained more than 71% of their initial activity at the end of 30 batch uses. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Bimagnetic hard/soft and soft/hard ferrite nanocomposites: Structural,magnetic and hyperthermia properties

Recent studies show that the chemical composition and shape of magnetic nanoparticles (NPs) play an important role in their properties. In particular, the bimagnetic NPs display useful and in many cases, more interesting properties than single-phase NPs. In this work, we prepared Fe₃O₄ and CoFe₂O₄ cube-like NPs and bimagnetic hard/soft (CoFe₂O₄/Fe₃O₄) and soft/hard (Fe₃O₄/CoFe₂O₄) nanocomposites (core/coating) using a facile and eco-friendly co-precipitation method that allows the synthesis of the cube-like NPs at temperatures near room temperature. The phase purity and the crystallinity of the NPs with a spinel structure were confirmed by the X-ray diffraction and infrared spectra techniques. Transmission electron microscopy (TEM) images revealed that the NPs have a cubic-like shape with an average dimension of 20 nm. Energy dispersive X-ray analysis, Mössbauer spectroscopy and SQUID magnetic measurements indicated the co-existence of Fe₃O₄ and CoFe₂O₄ phases in nanocomposites. In addition, the hysteresis loops exhibited a single-phase behavior in the nanocomposites that indicates there is a good exchange-coupling interaction between the hard and soft magnetic phases. The CoFe₂O₄/Fe₃O₄ nanocomposites presented a larger saturation magnetization than the CoFe₂O₄ NPs that is effective for their use in magnetic hyperthermia. Finally, we studied the hyperthermia properties of samples in an alternating magnetic field with a frequency of 276 kHz and field amplitude of 13.9 kA/m. Our results showed that magnetic hyperthermia efficiency simultaneously depends on the composition of samples along with magnetic anisotropy and saturation magnetization.